1. Field of the Invention
The instant invention relates generally to the production of textiles. More specifically, the instant invention relates to a textile machine belt that is used in the textile finishing process.
2. Background of the Invention
Depending on the circumstances, circular knit fabrics may be required to undergo successive processing operations during the preparation, dyeing, finishing and making-up thereof both in tubular form, as they descend from the circular knitting machine, and in open form, obtained by cutting the tubular fabric along one of its side edges. Generally, before undergoing wet treatments such as, for example dyeing, depending on the type or types of fiber which form the fabric, the fabric is subjected to a heat setting operation. In particular, heat setting is performed on fabrics composed of or partly containing synthetic fibers, such as thermoplastic fibers. The aim of heat setting is to fix the dimensions and the flat state of the surfaces of the fabric thereby providing the fabric with stability. Heat setting a fabric also eliminates permanent creases or distortions that occur during the course of processing in bleaching and dyeing machines.
With the currently available heat setting machines, it is not possible to differentiate between the processing of fabrics with an orthogonal pattern, i.e. of the weft/warp type, and the processing of knitted fabrics in general. This results in an increase in the duration of the processing cycle due to cutting and opening of the tubular fabric for heat setting and, sometimes, re-stitching of the fabric in a tubular form for the bleaching/dyeing operation, followed by reopening for the finishing and making-up operation. Moreover, these machines are unable to perform the heat setting of circular knitted fabrics, which must be completely processed in tubular form either for technical reasons, cost-related reasons or because of market requirements.
Processing of fabrics in tubular form without heat setting results in considerable risks from the point of view of quality and is only performed in exceptional cases. In the past, various attempts have been made to develop specific machines for heat setting fabrics in tubular form. However, the results obtained have been somewhat unsatisfactory. The known machines are characterized essentially by the method of conveying and guiding the tubular fabric and by the system for transferring heat to the fabric.
In some machines, the tubular fabric is guided by means of a flat expansion device and is fed in a flattened form between the surface of a heated steel cylinder and an endless felt belt. The main drawbacks of these machines include the squashing of the side edges of the tubular fabric and a non-uniform heat exchange on its two surfaces. In other machines, the tubular fabric is guided by means of a flat expansion device which accompanies it in a flattened form through a horizontal or vertical chamber until it emerges therefrom. Inside the chamber, the two surfaces of the tubular fabric are acted on by flows of hot air. The heat exchange on the two surfaces of the fabric, however, is inadequate.
In a new textile manufacturing process, an elastic belt having a definite length is used. During the manufacturing process, in a section of the machine used to heat set the textile or cloth being produced, the definite length elastic belt elongates from 50 to 70% of its original length. Currently, rubber and nitrile rubber belts reinforced with yarns or fibers having a standard elasticity are used in the new manufacturing process. In addition, belts made only with rubber have also been used. These types of belts, however, have exhibited a short service life when used in the new textile manufacturing process. The service life of these prior belts are shortened even more when subjected to the elevated temperatures in the heat setting sections of the textile manufacturing machine. Therefore, the temperatures that can be used in the manufacturing process are limited. Furthermore, the prior rubber belts experience excessive shortening in width in the cross-machine (CD) direction when elongated in the machine (MD) direction, which creates problems in the manufacturing process.
Attempts have been made to solve the problems associated with prior belts by utilizing belts coated with an elastic material. These attempts, however, have been unsuccessful since delamination of the coating from the belt occurs.
Accordingly, a need exists for a rubber belt that does not substantially shrink in width in the CD direction while it elongates from 50 to 70% of its original length in the MD direction. Furthermore, a reinforced rubber belt is needed that has a low risk of delamination between the rubber portion and the reinforcing portion of the belt while elongating in the MD direction. The instant invention is directed to overcoming these shortcomings associated with prior art belts.